Research on stress performance of universally wrapped assembled joints of lattice wind power tower with concrete-filled steel tube

Abstract

With the control parameters of the wall thickness of the ball table and the thickness of the pressure plate of the ball table, four universal wrapped assembled joint models were designed for the research of stress performance via static loading test. The failure mode of the joint, the axial force–displacement curve of the web member, the equivalent stress distribution of the ball table and the pressure plate of the ball table were analyzed, and the ABQAUS finite element software was used for the analysis of parameter expansion of the specimen. The research results show that the failure modes of universally wrapped assembled joints can be divided into the buckling failure of the ball table and the strength failure of the material. The wall thickness of the ball table is the key parameter affecting the failure mode of the joints, and the thickness of the pressure plate of the ball table is the crucial parameter influencing the ultimate bearing capacity of the joints. The maximum equivalent stress of the pressure plate and the ball table at compression zone for all the joints is occurred at the side squeezed by the bolt ball, and the growth rate of the equivalent stress for the ball table at compression zone is more uniform than that at tension zone. According to the finite element analysis results, when the wall thickness of the ball table is greater than 7 mm, the thickness of the pressure plate of the ball table is greater than 16 mm, the growth rate of the ultimate bearing capacity of the joint is significantly decreased, therefore, it is recommended to use the wall thickness of 7 mm and the pressure plate thickness of 16 mm in the actual design of the project.